1. Field of the Invention
Embodiments relate to a polymer composition, a hardmask composition having antireflective properties, and associated methods. More specifically, embodiments relate to a hardmask composition including at least one aromatic ring-containing polymer with a strong absorption in the short wavelength region (e.g., 157 nm, 193 nm and 248 nm).
2. Description of the Related Art
There is a continuous demand to reduce the size of structural shapes in the microelectronics industry and other related industries, including the manufacture of microscopic structures (e.g., micromachines and magneto-resist heads). In the microelectronics industry, there exists a need to reduce the size of microelectronic devices in order to increase a number of circuits in a given chip size.
For better resolution in some lithographic processes, an antireflective coating (ARC) may be used to minimize the reflectivity between an imaging layer, e.g., a radiation-sensitive resist material layer, and an underlying layer. However, since many portions of the imaging layer are removed during etching of the ARC after patterning, patterning may be further required in the subsequent etching step.
In other words, in some lithographic imaging processes, the resist may not provide resistance to the subsequent etching step to an extent sufficient to effectively transfer the desired pattern to a layer underlying the resist. In actual applications (e.g., in the case where an ultra-thin resist layer is required, an underlying material to be etched is thick, a large etching depth is needed, and/or the use of a particular etchant is required depending on the type of an underlying material), a ‘hardmask layer’ may be used as an intermediate layer between the patterned resist layer and the underlying material to be patterned by transfer from the patterned resist. The hardmask layer should be able to receive the pattern from the patterned resist layer and withstand etching required to transfer the pattern to the underlying material. Thus, a hardmask composition that may be etched with high etch selectively through an overlying photoresist or overlying layer materials (in case of a multilayer etching process) as a mask, while being resistant to etching necessary to pattern an underlying layer, particularly, an underlying metal layer, through a hardmask as a mask would be desirable.
Although a number of hardmask materials, e.g., amorphous carbon layers, are known, there is a continuous need for an improved hardmask composition. Since conventional hardmask materials may be difficult to apply to substrates, the use of chemical and physical vapor deposition, special solvents, and/or high-temperature baking may be required. Further, there may be difficulty in controlling contamination from particles when conventional hardmask materials are formed by deposition. Thus, a hardmask composition that can be applied by a spin-coating technique without the necessity of high-temperature baking would be desirable. A hardmask composition that provides superior storage properties, can be applied by a spin-coating technique and avoids unwanted interactions (e.g., acid pollution from a hardmask) with an imaging resist layer would further be desirable. A hardmask composition that has particular optical properties against imaging radiation at shorter wavelengths (e.g., 157 nm, 193 nm, and 248 nm) would also be desirable.